PF000560 FlushSMART Toilet Tank Optimizer Water Displacement Bag - Reduce the water used on each flush by hanging this maintenance-free device in the toilet tank to displace water without decreasing flushing performance. Simply fill bag with water, hang in toilet tank and start saving up to 2.5 quarts with every flush. Save water and save money. Easy to use with instructions printed directly on bag. Valve is self sealing and anti-evaporative. Saves up to 4,000 gallons of water annually. Features: -Displacement bag. -Instructions printed right on bag. -Non-corrosive, heavy duty pinhole free PVC construction. -Perfect for home or office. -Easy to use - non-toxic. -Water, energy and money saver.